Swimming pool oxidation

Fig. 6.3-16 Tabletting of swimming pool oxidizer compound with a rotary punch-and-die press (courtesy Stellar, Sauget, IL, USA) Fig. 6.3-17 Some different shapes of tablets for swimming pool sanitizing (courtesy Stellar, Sauget, IL, USA)...

Tetrasilver tetroxide is a powerful oxidizer for sanitizing swimming pools, hot tubs, and industrial cooling system waters (see Water, treatment of SWIMMINGPOOLS, SPAS, AND HOT tubs). This oxide is slightly soluble and its dissociation into silver ions is enhanced by the addition of the oxidizer KgSgOg. Bivalent and trivalent silver disinfectants have been shown to be from 50 to 200 times more effective as sanitizers than monovalent silver compounds. 

However, these systems have been shown to be ineffective in either disinfection, algae prevention, or oxidation of swimming-pool contaminants. 

Urea (24), amino acids (25), and creatinine (26) are also decomposed during superchlorination or shock treatment, with formation of N2 and other oxidation products. However, the process is slower than with ammonium ion (see Chloramines and BROMAMINEs). Urea is the principal nitrogen-containing compound in swimming pools. Since it is an amide, it reacts slowly with chlorine, yielding N2, NCl, and NO/ (27). 

High yields of NaOCl are obtained electrolyticaHy by oxidation of CT at dimensionally stable anodes (219). Sodium hypochlorite is prepared using small diaphragmless or membrane cells, with a capacity of 1—150 kg/d of equivalent CI2, which produce a dilute hypochlorite solution of 1—3 and 5—6 g/L from seawater and brine, respectively (see Chemicals from brine). They are employed in sewage and wastewater treatment and in commercial laundries, large swimming pools, and aboard ships. 

ElectrolyticaHy generated hypochlorite may be used for the oxidative destmction of cyanides (qv) or the sterilization of domestic wastes. Several on-site systems for swimming pool sterilization and municipal waste treatment works have been developed. One of these systems is described in Reference 124. On-site production and immediate use of chlorine is considered safer than the transportation of chlorine. 

Chlorinated water. The oxidizing power of chlorine-containing chemicals keeps swimming pool watar free of disease-causing microorganisms. 

Oxidizing bleaches kill microbes by reacting with cell membranes and cell proteins. The most widely used is sodium hypochlorite for household and hospital uses, and calcium hypochlorite for drinking water and swimming pool disinfecting. 

PHMB is very toxic to fish and aquatic life. It is moreover irritating to skin and may cause sensitization by skin contact. It can cause irritation to the eyes, nose and respiratory tract. The PHMB is not compatible with most common swimming pool chemicals. Not compatible with chlorine and chlorinated chemicals and bromine donors. Not compatible with ionic sterilizers, copper based QAC-algicides, anionic detergents, water softening chemicals, persulfate oxidants etc. The defence of the inventors of PHMB is that one should not combine it with other biocides because it should be a bactericide/algicide. But the algicidal properties of PHMB are very weak in brochures and manuals the dose is 200 ppm. 

WSCP Enhances the Activity of Oxidizing Mfcrobicides In Swimming Pools... 

Fi-Clor 60S , Brochure NH/FS/67.4, Loughborough, Fisons, 1967 This compound (sodium dichloroisocyanurate), used in chlorination of swimming pools, is a powerful oxidant and indiscriminate contact with combustible materials must be avoided. Ammonium salts and other nitrogenous materials are incompatible in formulated products. The dibromo analogue, used for the same purpose, will behave similarly. 

This compound, used in chlorination of swimming pools, is a powerful oxidant, and indiscriminate contact with combustible materials must be avoided. The tribromo analogue would be similar. 

Although solutions of sodium hypochlorite are useful oxidizing agents, the solid is not very stable. Calcium hypochlorite is used in bleaches, swimming pool treatments, and so forth. The decomposition of OC1- is catalyzed by compounds containing transition metals. 

Noncertified colors, 12 51 Noncertified pigments, performance criteria in cosmetic use, 7 860t Non-cGMP products, 11 427, 433 Non-chemical stabilization methods, in PTG systems, 19 366 Nonchlorinated pesticides and herbicides bioremediation, 3 776—779 Nonchlorine oxidizers, in swimming pools, 26 189-190... 

Contamination of silicon wafers by heavy metals is a major cause of low yields in the manufacture of electronic devices. Concentrations in the order of 1011 cm-3 [Ha2] are sufficient to affect the device performance, because impurity atoms constitute recombination centers for minority carriers and thereby reduce their lifetime [Scl7]. In addition, precipitates caused by contaminants may affect gate oxide quality. Note that a contamination of 1011 cnT3 corresponds to a pinhead of iron (1 mm3) dissolved in a swimming pool of silicon (850 m3). Such minute contamination levels are far below the detection limit of the standard analytical techniques used in chemistry. The best way to detect such traces of contaminants is to measure the induced change in electronic properties itself, such as the oxide defect density or the minority carrier lifetime, respectively diffusion length. 

In addition to drinking water, chlorinated oxidants reacting with organic materials will lead to the formation of chloroform in swimming pools. Since swimming pools are not routinely analyzed for their chloroform content, data are limited and derived from special studies. Such studies will often cover the broader family of THMs, and while chloroform levels in blood or alveolar air samples will be reported, the environmental agents will often simply be recorded in terms of THMs. A rule of thumb (Copaken 1990) is... 

Sodium hypochlorite NaOCl is a strong oxidizer used in swimming pools, and when diluted to 5.25%, it is known as the laundry bleach Clorox. 

The hypochlorous acid oxidizes the cell walls and kills bacteria. Solid calcium hypochlorite, Ca(OCl)2, and liquid solutions of sodium hypochlorite, NaOCl, can be used to generate hypochlorous acid in place of chlorine gas, for example, in chlorinating swimming pools. The hypochlorite ion generated from Ca(OCl)2 and NaOCl forms an equilibrium with water represented by the equation ... 

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